Heat exchange unit



June 7, 1932- A. s. LIMPERT HEAT EXCHANGE UNIT Filed Dec. 19. 1929Patented June 7, 1932 ALEXANDER S. LIMPERT, OFIBAY SHORE, NEW YORK HEATEXCHANGE UNIT Application filed December 19, 1929, Serial No. 415,181.

unit can be formed from various metals as a result of either a casting,a die-stamping or a pressure die-castin operation and which 10 unitreadily lends itself, ,"when,constructed of ferrous metal, to beingfinished in enamel. Other objects of the invention are hereinafter setforth.

Heretof0re, as I am well aware, it has been proposed, as for example inmy Patent No. 1,706,621 to cast a coil or high conductivity, such ascopper for example, in a wall of a metal of lower melting point, suchfor example, as type metal, or other zinc alloys or even aluminum, butwhile tanks having such coils cast in the walls thereof are quiteefficient as cooling units, nevertheless, there are many objections,such as casting di'fiiculties, especially when the number of rejectionsare taken into consideration, the susceptibility of metal such as copperto form scale on the inside thereof during the casting operation, whichscale in the presence of many refrigers ants tends to copper plate thevalve-seats and bearings and other portions of a mechanicalrefrigerating machine and also the tendency to form air pockets betweenthe coil and the metal wall in which the same is embedded due to thedifference in the coeflicients of expansion of the two metals. Also suchcooling units cannot be enamelled satisfactorily,

since in the vitreous enamelling the temperatures are so high as to inmany cases burn the 0011 besldes forming scale as aforesald there n. (0

present time to form such tanks of ferrous metal, such as steel or iron,as' it is extremely tremely diflicult tedious expensive operation.v

My investigations have led to the discovery of a new heat exchangedevice which is reotherwise formed on the outer wall of the body, thesame extending completely around Neither is it considered practicable atthe markably efficient and which overcomes the aforesaid objections, thesame being fully set forth in the following description and drawingforming a part thereof.

Referring to the drawing wherein I have illustrated differentembodiments of the invention:

Figure 1 is a longitudinal ielevation, partially in section, of acooling unit embodying my invention; 1

Fig. 2 is a plan view, from below, of the same unit;

Fig. 3 is a front'elevation thereof;

Fig. {1 is a fragmentary perspective view, partially in section, of amodification;

F ig. 5 is a fragmentary vertical section of a still furthermodification wherein a tube of circular cross section is employed forconstruction of the coil element. v

In the construction shown in Figs. 1, 2 and 3 inclusive, thereferencenumeral 1 designates the shell or body proper of the coolingunit, the same being as shown of generally circular crosssectionexcept'that the same is flattened at the bottom thereof. Said bodyisprovided with radially extending fins 2 which are positioned atintervals along the length thereof and preferably cast or formedintegral with the body proper. These fins are cut away as indicated bythe reference letter 3 so that no portion thereof projects below thelowermost limits of the flat-body, all for the; purposes hereinaftersetforth. A series of peripheralgrooves 3 are cast or the curvilinealportion of the body, but being interrupt-ed at the bottom thereof andthese grooves serve to receive a flattened coil, preferably of softpliable metal, such as lead, the terminals a of such coil beingofcircular cross section and being equipped with suitable fittings 6having threaded ends 0, whereby such coil can be hermetically connected"into the refrigerant line of the machine with which such cooling unit isintended to be associated. Said body is preferably provided with anintegral boss 5 in which is drilled or otherwise formed a thermostatwell 6, the

' latter being positioned adjacent the rear end of the body so that itwill be subjected to the temperature conditions in general proximity tothe rear terminal of the coil. Said body member 1 is provided with agenerally cylindrical central chamber 7 which is flat at the bottomthereof and sub-divided byone or more series of opposing partitions orin ternal' fins 8 which serve to receive ice trays when the same areinserted-in said chamber. The shell 1 atthe front and rear thereof isprovided with rectangular plates or supports 9 and 10, respectively,cast integral therewith or otherwise secured thereto, the

the crossover section 6 of the flattened coil frombeing accidentallydisplaced or in ured I 2 with the sides and bottom of the flattened Iduring the handling of such unit, as well as serving as spacers tomaintain such unit out of direct contact with the surface upon which theendplates of such coil are supported. At

the sides and top however, ,these end plates extend but a slightdistance beyond the outermost limits of the cooling vanes 2. I

In Fig. 4 I have illustrated a construction, in which in lieu of theseries of annular grooves on the periphery of the body 1 for thereception of the flattened coil 4, I provide at intervals around theperiphery of the body 1', opposing lugs 11 which serve as a guide forsuch coils during the application of the same to the bodytl and also toeffectively maintain such coils in position once the same are applied tosuch body. While such construction does not afford the extended surfacecontact afforded by the annular grooves 3 of the construction shown inFigs. 1 and coil 4, nevertheless, this modified cons truction is alsohighly efficient since not only is a very substantial part of the 'coil4 in intimate metal-to-metal contact with the body" -1, but the balanceof its periphery will be directly exposed to the air currents in therefrigerating machine and thereby effectively serve to cool the same.

In Fig. 5 I have illustrated a stillfurther modified construction inwhich I provide semi-circular grooves 3, generally corresponding intheir arrangement to the flattened grooves 3 of the construction shownin Figsgl and 2, and in, these grooves is mounted a coil of circularcross section, there} by affording substantially 50% metal-tometalcontact between the periphery of the cooling pipes 4 andvthe body 1';This construction is likewise highly eflicient although for'manypurposes the construction shown in Figs. 1 and 2 is preferred not onlybecause mat'ely two-thirds of the peripher with the body 1.

enamellin the coils are less conspicuousbut also because I of the moreextended metaLto-metal contact between the coilsand the body 1, sinceconsiderably more than one-half and appfroxhlflattened coil 4 is inmetal-to-meta contact My improved itself to rapid assembly since thebody proper, which maybe castor formed by a stamping operation, can bemounted on the mandrel of a lathe whereupon the coils can be quickly andeasily applied in a proper position in the grooves 3 or 3, or betweenthe lugs 11", during the'slow rotation of said body. As shown, thegrooves 3' and 3 are construction readily lends interrupted and also'aspreviously explained, T

the vanes or fins 2 are cut away at the bottom of the body so that alength of tubing can be continuously wrapped or applied to the bodywithout the crossover sections e being interfered with by thesaid vanesor fins 2 and this is particularly important because it permits of saidcoil being applied in the manner described during the rotation of thebody on a suitable spindle orv mandrel. Following the application of thecoil to the body,

the fittings b are applied to the circular or unflattened ends a thereofin such a manner that such ends project either flush with or slightlybeyond the outer ends of such fitting, whereupon the ends of saidfittingand the ends of said I pitpe are brazed or soldered together andsaid tti ng is then threaded as 'indicatedby the reference letter 0. Theend ipes are then applied to the body and the ttings are secured inposition on said'end plates by a means of thescrews d.

Prior'to the application of the coils to the bod proper, the entireinternal and external 'sur ace of the body may be enamelled, with the,possible exception of the grooved 'por tions thereof, which portions, ifdesired, can

be protected with asuitable-coating during the enamelling operation, andfollowing the operation, the coils can be up plied to t e body in themanner, previously described whereby a highly; attractive internally andexternally non-corrosive unit is 7 obtained, which is also thermallyhighly efficient insofar as the heatexchange properties a areconcerned.-

, 'While I preferably employ a cast iron shell,

or body which is either completely enamelled or is enamelled on itsentire inner and outer surfaces, with the exception of the surface andapplied to saidlshell, nevertheless, I can, I

if desired, construct a shell of aluminum or die-casting operation, andI may apply to such'shell a coil of a different metal, such for exampleas a copper coil or an aluminum coil other suitable metal, formed ifdesired by a which may be of rectangular configuration or of circularcross section, as desired.

By virtue of the construction of my improved tank, it is'possiblertoapply the coil thereto while maintaining the tube under considerabletension and thereby substantially all air gaps between the coil and theouter wall of the shell to which 'it is applied are eliminated.Furthermore, by virtue of the fact that the joint between the margin ofthe grooves and the adja cent wall of the tubing'will be exposed, tomoisture laden air when the unit is used for refrigeration purposes, anyair gaps will soon become filled with water which will be quicklyconverted into ice within a few minutes after the refrigeratingoperation-is commenced and such ice will of itself form an excellentbond or contact across such gap.-

ing is bein wound thereon under tension, the

shell may e supported and held in a stationary position and the tubeapplied thereto from a rotating reel.

My improved heat exchanger, when employed as a cooling unit forrefrigeration purposes, provides a sharp cooling chamber which can bemaintained, depending of course on the adjustment of a'thermostaticcontrol such as is commonly employed for such purposes, within a verysmall range of temperature, particularly since by virtue of theconstruction of the unit thev same serves as a storage or hold-overreservoir, and thereby. is ideally suited for refrigeration purposes.

- tective film of enamel or the like'not exceed ing 1/100 of an inch asdistinguished from a substantial insulating coating of enamel orstantially exceeds 2/100 of an inch in thickness. v The term linecontact as used in the claims, refers to the contact in a planecorresponding to a cross-section through'the coil and the walls.adjacent thereto as distin+ guished from the substantially point contactin thesame plane of a tube of circular cross section with a flat surfacebrought into intimate contact therewith.

Various modifications within the scope of the appended claims may bemade without departing from the spirit of my invention.

Having thus described my invention, what I claim and desire to obtain byUnited States Letters Patent is 1. In a heat exchan er the combinationcomprising a metal bo y having a chamber therein and a coil of flattenedtubin' wound around said body, said coil throughout the greater portionof its length having extended line contact throughout the greaterportion of its peripheryand in planesextending trans- 'versely of itslongitudinal axis, with the exits periphery and in planes extendingtrans versely of the longitudinal axis of the tubing,

with the exterior of said body.

3. In (a heat exchanger, the combination comprising a body of curvilmealexternal configuration havlng a-length of tubing externally coiledtherearound in intimate line con- In lieu of rotating the shell whilethe tub-.

tact, in planes extending transversely of the longitudinal axis of thetubing, with the exterior of said body, said body being provided withradiating fins extending outwardly fromthe periphery of said body at anangle to the longitudinal axis of such body and the adjacent loops ofsaid coil being interconnected by integral cross-over portionswhich arealso in intimate line contact, in planes transverse to the longitudinalaxis of such grtziss-over port-ions, with the exterior of said 4. Asharpcooling unit, comprising a metal shell having a sharp cooling chambertherein,said shell being generally curvilineal in configuration andhaving a flattened bottom,- a series of flanges projecting at intervalsfrom the outer periphery of said shell, the

individual flanges extending around the greater portion of shellperiphery and being interrupted at the bottom of the shell periphcry anda length of metal tubin wound on said shell and in intimatemetal-to-metal con- 7 tact therewith throughout the greater portion ofthe periphery of such tubing, said tubing extending transversely'of theshell beshell at the shellbottom, the transverse and longitudinalportions of such tubing being integral with each other.

5. A sharp cooling unit, comprising a curvilineal shell having a seriesof integral transverse flanges projecting at intervals along the shellfrom its outer periphery and a plurality of grooves formed on the outerperiphery of the shell, the different grooves lying between differentadjacent flanges and said grooves being interrupted at the bottom ofsaid shell and a length of metal tubing wound on said shell along andWithin said grooves, the tubing in adjacent grooves being successivelyinterconnected longitudinally along the bottomfofsaid shell. A

6. In a heat exchanger, the combination comprising a metal shellhaving-"a central chamber therein and having a serles of transtween theflanges and longitudinally of theverse grooves extending almost butnotcoming successively connecting the-tubing in the different grooveslongitudinally of said shell;

1 7. In a heat exchanger, the combination- 5 pletely around itsperiphery a continuous length of metal tubing positioned in saidgrooves, each groove being of such configuration that the transverse,length of the surface of the groove-isat least substantially equal toone-half the transverse perimeter of the tubing positioned thereinwhereby intlmate metal-to-metal contact between the surface of eachgroove andthe tubing therein is insured and integral cross-over sectionsof tubcomprising a metal shell having a series of spaced .g'rooves onthe external thereof, said grooves extending a most but not completelyaround saidshell and a metal coil wound around said shell, thedifi'erent loopsof said coil being located in and by different groovesand a transverse section of said 'coil and said grooves having intimatemetal-to-metal contact with each other at any location along the lengthof said grooves throughout considerably more than one-half of thetransverse periphery of such coil.

Signed at New York, in the county and State of New York, this 14th dayof December, 1929.

- rALEXANDER S. QLIMPERT.

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